Although I can't find the download anywhere, Apple has posted several KB articles on Xsan 2.2. I guess they want us to be good and ready for the release.

• Xsan 2.2: Enabling extended attributes
• Xsan 2.2: How to set Spotlight search levels
• Xsan 2.2: Avoid using native extended attributes with StorNext clients
• Xsan 2.2: "fsmpm not running" message in Xsan Admin
• Xsan: Install Xsan 2.2 Update for 10.6 after installing Mac OS X v10.6
• About the security content of Xsan 2.2

They also updated a few older articles...

• Xsan: Compatibility of Xsan metadata controllers (MDCs) and clients
• Xsan 2: Optimizing file system journal size
• Xsan 2: "The item will be deleted immediately" or "-1407" alert when moving items to the Trash